A Study of an Erosion-Affected Reach of the River Beki Using Mathematical Modeling

The Beki River basin, Assam, India is the major southward draining interstate river basin which has a trans-boundary counterpart called Kurichu in Bhutan. The river and its drainage channels flow through the plains of Assam for about 85 km and drain an area of 26,243 sq. km. approximately. Erosion and the recurring floods of characteristically high magnitude by Beki River have been heavily affecting the agricultural lands, crops, cattle and people of Barpeta district of Assam. As such, the need for extensive model studies, for evaluating the performance of different structural and river training and bank protection measures is highly recommended. Therefore, a two dimensional mathematical model for simulating unsteady flow in this river is programmed for evaluation of the effectiveness of the new anti-erosion structures. Using the model, some areas of the river reach are provided with some non-submersible spurs, depending upon the vulnerability. However, considering economic feasibility, optimization has been done to select the viable option for practical applications. This resulted in reduction of flow velocity in the protected portions while higher flow velocity could be observed in unprotected portions of the bank.